1. Field of the Invention
This invention relates to a coffee making apparatus for obtaining coffee from unroasted dried coffee beans through the steps of roasting the unroasted dried coffee beans, milling the roasted coffee beans and extracting the coffee granules.
2. Description of the Prior Art
The inventor of this invention proposed a coffee making apparatus for automatically obtaining coffee from unroasted dried coffee beans. The coffee making apparatus has a roaster for roasting unroasted dried coffee beans, a milling/extracting unit for milling the unroasted dried coffee beans into coffee granules and thereafter extracting coffee from the coffee granules, an air blower for blowing air into the milling/extracting unit, a pouring unit for pouring hot water onto the coffee granules to produce water-and-coffee-granule mixture, and a coffee server for receiving a coffee solution filtered from the water-and-coffee granule mixture.
However, at least the roasting of unroasted dried coffee beans, the cooling of the roasted coffee beans, the milling the cooled roasted coffee beans and the extracting coffee solution are carried out in a cycle in this order and thus the next coffee making cycle cannot be started until the extraction of the coffee solution by the milling/extracting unit or the reception of the coffee solution by a coffee server in the previous cycle ends. Since, therefore, the new step of roasting coffee beans cannot be carried out during the extraction process in the previous cycle, a lot of cups of coffee cannot be made at a high efficiency.
In this coffee making apparatus, hot water is uniformly poured by the pouring unit on the substantially whole upper surface of coffee granules deposited in the milling/extracting unit. In this respect, the layer-portion of the coffee granules lower than a rotary cutter is likely to become denser when a coffee solution is extracted from water-and-coffee-granule mixture by means of the milling/extracting unit provided, at the vicinity of the bottom portion thereof, with the rotary cutter. This coffee making apparatus, in which the uniform pouring step is employed, is encountered with a problem that the layer-portion of the coffee granules lower than the rotary cutter hinders extracted hot water from flowing down through a filter and a long time is required for the filtration of an extracted coffee solution. The apparatus has a further problem that a coffee solution to be extracted overflows from the milling/extracting unit. The apparatus has a still further problem that the milling/extracting unit cannot extract a coffee solution in an ideal manner.